The present invention relates to a head-level microactuator having improved efficiency and improved ease of manufacture. More particularly, it relates to a magnetic microactuator located between a suspension and a slider in a disc drive system to selectively move a transducing head radially with respect to a rotatable disc.
The density of concentric data tracks on magnetic discs continues to increase (that is, the size of data tracks and radial spacing between data tracks are decreasing), requiring more precise radial positioning of the head. Conventionally, head positioning is accomplished by operating an actuator arm with a large-scale actuation motor, such as a voice coil motor, to radially position a head at the end of the actuator arm. The large-scale motor lacks a sufficient resolution to effectively accommodate high track-density discs. Thus, a high resolution head positioning mechanism, or microactuator, is necessary to accommodate the more densely spaced tracks.
One promising approach for high resolution head positioning involves employing a high resolution microactuator in addition to the conventional lower resolution actuator motor, thereby effecting head positioning through dual-stage actuation. Various microactuation designs have been considered to accomplish high resolution head positioning. One design involves inserting a silicon-based thin film structure between the suspension and the slider in a disc drive assembly. A major technical challenge in implementing such a microactuator is to provide sufficiently large actuation force to overcome friction forces and spring bias forces to drive the head at a speed high enough to accommodate the required bandwidth. Such a design must be realized in a relatively small wafer area to keep costs reasonable and to allow easy integration into the disc drive design.
There is a need in the art for a microactuator design providing large actuation force with reasonable power consumption and within a reasonable wafer area to microposition a transducing head at a speed that accommodates the high bandwidth required by high performance disc drives and can be manufactured cost effectively.
The present invention is a dual-stage actuation assembly for positioning a slider carrying a transducing head in a disc drive system with respect to a selected radial track of a rotatable disc. The dual-stage actuation assembly includes a movable actuator arm controlled by an actuator motor and a suspension assembly, including a flexure, supported by the actuator arm. The assembly includes a microactuator having a stator attached to the flexure and a rotor attached to the slider. The rotor is transversely movable with respect to the stator and a horizontal plane generally parallel to the surface of the disc. The assembly contains a magnetic circuit arranged vertically in a plurality of horizontal planes configured to effect motion of the rotor with respect to the stator.